Pye AM/FM Piper P117. - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

bobhowe · 31st Jul 2021, 7:08 pm

Hi David could you scope both P117 and compere readings for hum on the other one and find out why both hopeless on LW

Edward Huggins · 28th Nov 2021, 9:52 am

On revisiting the design of that ECL82 AF stage, it still looks capable of good audio with its NFB and use of the OPTX primary to aid smoothing - and if it were on a well spaced out chassis - but not possible in the dreaded compact Piper. A limiting factor might well be "that" very low value grid coupling cap?

31st Jul 2021, 7:08 pm	#41
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Pye AM/FM Piper P117. Hi David could you scope both P117 and compere readings for hum on the other one and find out why both hopeless on LW

28th Nov 2021, 9:52 am	#42
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,328	Re: Pye AM/FM Piper P117. On revisiting the design of that ECL82 AF stage, it still looks capable of good audio with its NFB and use of the OPTX primary to aid smoothing - and if it were on a well spaced out chassis - but not possible in the dreaded compact Piper. A limiting factor might well be "that" very low value grid coupling cap? __________________ Edward.